U.S. patent number 11,089,699 [Application Number 16/846,203] was granted by the patent office on 2021-08-10 for rollable display.
This patent grant is currently assigned to LG DISPLAY CO., LTD.. The grantee listed for this patent is LG Display Co., Ltd.. Invention is credited to MiJin Han, SeungHee Lee, HeongSoo Park.
United States Patent |
11,089,699 |
Park , et al. |
August 10, 2021 |
Rollable display
Abstract
Disclosed is a rollable display, which prevents slippage between
a flexible display panel and a back plate attached to the flexible
display panel for supporting the same. The rollable display has a
feature in different patterns of the back plate for each area. In
addition, the rollable display has a feature in that a display unit
is foldable and non-foldable via a link unit so as not to be folded
or rolled multiple times in the same direction.
Inventors: |
Park; HeongSoo (Goyang-si,
KR), Lee; SeungHee (Goyang-si, KR), Han;
MiJin (Gimpo-si, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
LG Display Co., Ltd. |
Seoul |
N/A |
KR |
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Assignee: |
LG DISPLAY CO., LTD. (Seoul,
KR)
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Family
ID: |
1000005732947 |
Appl.
No.: |
16/846,203 |
Filed: |
April 10, 2020 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200245477 A1 |
Jul 30, 2020 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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16177048 |
Oct 31, 2018 |
10694625 |
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Foreign Application Priority Data
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Oct 31, 2017 [KR] |
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10-2017-0144082 |
Oct 8, 2018 [KR] |
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10-2018-0119836 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05K
1/189 (20130101); H04M 1/0268 (20130101); G09F
9/301 (20130101); G06F 1/1652 (20130101); H05K
5/0217 (20130101); H01L 51/524 (20130101); H05K
5/0017 (20130101); H05K 2201/10128 (20130101); H01L
27/323 (20130101); H01L 2251/5338 (20130101); H01L
27/3276 (20130101) |
Current International
Class: |
G06F
1/16 (20060101); G09F 9/30 (20060101); H05K
5/00 (20060101); H04M 1/02 (20060101); H01L
51/52 (20060101); H05K 5/02 (20060101); H05K
1/18 (20060101); H01L 27/32 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2777620 |
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May 2006 |
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CN |
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101814258 |
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Aug 2010 |
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CN |
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103069473 |
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Apr 2013 |
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CN |
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203517224 |
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Apr 2014 |
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CN |
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105514115 |
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Apr 2016 |
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CN |
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205881905 |
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Jan 2017 |
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CN |
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106373490 |
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Feb 2017 |
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CN |
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106816094 |
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Jun 2017 |
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CN |
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107102692 |
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Aug 2017 |
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CN |
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3 173 897 |
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May 2017 |
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EP |
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10-2009-0075331 |
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Jul 2009 |
|
KR |
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Other References
Chinese Office Action dated Aug. 5, 2020 issued in corresponding
Patent Application No. 201811286009.8 with English Translation (22
pages). cited by applicant .
European Search Report dated Feb. 28, 2019 issued in the
corresponding European Patent Application No. 18203699.6, pp. 1-8.
cited by applicant .
Chinese Office Action dated Feb. 8, 2021 issued in Patent
Application No. 201811286009.8 w/English Translation (24 pages).
cited by applicant.
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Primary Examiner: Wilson; Adrian S
Attorney, Agent or Firm: Polsinelli PC
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a Divisional of application Ser. No.
16/177,048, filed Oct. 31, 2018, which claims priority to and the
benefit of Korean Patent Application Nos. 10-2017-0144082 filed on
Oct. 31, 2017 and 10-2018-0119836 filed on Oct. 8, 2018, all of
which are hereby incorporated by reference in their entirety as if
fully set forth herein.
Claims
What is claimed is:
1. A rollable display comprising: a display unit including a
flexible display panel having a front surface where an image is
displayed and a back plate disposed in contact with a rear surface
of the flexible display panel and provided with a plurality of
alternately arranged folding portions and non-folding portions; and
a link unit coupled to a rear surface of the back plate to allow
the folding portions of the display unit to alternately fold
inwardly and outwardly in multiple times, wherein the link unit
includes: a plurality of first shafts coupled to the non-folding
portions in a first direction on the rear surface of the flexible
display panel; a first link joint rotatably coupled to each end of
a corresponding first shaft; and a second link joint coupled to the
first shaft at an outer side of the first link joint.
2. The rollable display according to claim 1, wherein one end of
the first link joint of the first shaft is connected to an upper
end of the second link joint, which is coupled to each end of a
second shaft, which is disposed at a front of the first shaft in
the first direction, and the other end of the first link joint of
the first shaft is connected to a lower end of the second link
joint, which is coupled to each end of a third shaft, which is
disposed at a rear of the first shaft in the first direction,
wherein one end of the second link joint of the first shaft is
connected to an upper end of the first link joint, which is coupled
to each end of the third shaft, which is disposed at the rear of
the first shaft in the first direction, and the other end of the
second link joint of the first shaft is connected to a lower end of
the first link joint, which is coupled to each end of the second
shaft, which is disposed at the front of the first shaft in the
first direction, and the first and second link joints are rotated
in cooperation with each other.
3. The rollable display according to claim 2, wherein the display
unit is unfolded to a planar form when the first link joint rotates
in a given direction and the second link joint rotates in an
opposite direction about a rotation axis of the first shaft, and
wherein the display unit is folded to have a plurality of folding
regions when the first link joint rotates in the opposite direction
and the second link joint rotates in the given direction.
4. The rollable display according to claim 3, wherein the display
unit includes at least one hook member provided on a rear surface
of each unfolding portion of the back plate and coupled to a
corresponding one of the first to third shafts to fix the display
unit to the link unit.
5. The rollable display according to claim 4, wherein a position
where the hook member coupled to the first shaft does not interfere
with a position where the hook member is coupled to the second
shaft or the third shaft.
6. The rollable display according to claim 3, further comprising a
side shaft disposed parallel to the first shaft to connect at least
one end of both ends of the first link joint, wherein the rear
surface of the display unit is supported by or coupled to the side
shaft.
7. The rollable display according to claim 1, further comprising a
printed circuit board connected to one end of the display unit,
wherein the printed circuit board is formed to have a length equal
to or shorter than a length of the first link joint or a length of
the second link joint.
8. The rollable display according to claim 1, wherein a length of
the first link joint is the same as a length of the second link
joint.
Description
BACKGROUND
Field of the Disclosure
The present disclosure relates to a rollable display, and more
particularly, to a rollable display, which prevents slippage
between a display panel and a back plate for supporting the
same.
Description of the Background
An image display, which reproduces various pieces of information on
a screen, is a core technology of the information and communication
age, and is being developed in the direction of becoming thinner,
lighter, and having higher performance. Thus, as a flat panel
display capable of reducing the disadvantageous weight and volume
of a cathode ray tube (CRT), for example, an organic light-emitting
display, which enables self-luminescence and obviates a light
source unit, is in the spotlight.
In such an organic light-emitting display, a plurality of pixels is
arranged in a matrix form to display an image. Here, each pixel
includes a light-emitting element and a pixel-driving circuit
constituted by a plurality of transistors, which drive the
light-emitting element independently of each other.
Recently, with regard to various applications, there is increasing
demand for a flexible display, which is easy to carry in a pocket
or a small pouch and is capable of displaying an image on a larger
screen than when being carried. Such a flexible display is folded
or partially bent when it is carried or stored, but is unfolded
when displaying an image, which may increase an image display area
and may cause an increase in user visual sensation and viewing
realism.
In particular, among various shapes of flexible display devices, a
lot of research has been conducted on a rollable display due to the
advantages of superior portability and an increase in the area of a
display when unrolled compared to when rolled.
FIG. 1 is a view illustrating a typical rollable display.
As illustrated in FIG. 1, a display panel 10 is attached onto a
plate 20 having supporting force to constitute a display unit.
Then, in the state in which the display unit is wound around a
single-axis roller (not illustrated), the end of the display unit
is unwound from the roller in order to use the display unit for
display.
Here, an adhesive layer (not illustrated) is disposed between the
display panel 10 and the plate 20 to attach the same to each other.
Since the plate 20 is rolled at the inner side along a
circumference smaller than that of the display panel 10, the
greater the number of turns, the greater the difference in path
between the plate 20 and the display panel 10 due to the difference
in circumference. Therefore, when wound two or more turns around
the roller, the plate 20 is pushed a long distance from the display
panel 10 at the end of the display unit.
The display unit is wound around the roller in the stored or
portable state of the rollable display, and is unwound starting
from the end thereof only when used for display. When slippage
between the plate 20 and the display panel 10 is severe in the
state in which the display unit is wound around the roller, the
adhesive layer between the plate 20 and the display panel 10 may be
deformed so that the two are fixed in a slipped and deformed state.
As a result, when the display unit of the rollable display is
unwound from the roller so that an image is displayed on the end of
the display unit, a slippage defect occurs. In particular, such
slippage occurs not only between the plate 20 and the display panel
10 but also sequentially occurs between respective layers provided
in the display panel 10, the adhesive layer, and the plate 20. This
is visible as wavy uneven portions when displaying an image, which
deteriorates visibility.
SUMMARY
Accordingly, the present disclosure is directed to a rollable
display that substantially obviates one or more problems due to
limitations and disadvantages of the related art.
The present disclosure has been provided to solve the problems
described above, and an object of the present disclosure is to
provide a rollable display, which prevents slippage between a
display panel and a back plate by varying the shape of the back
plate when the back plate is stored in an accommodating case (e.g.,
housing).
Additional advantages and features of the disclosure will be set
forth in part in the description which follows and in part will
become apparent to those having ordinary skill in the art upon
examination of the following or may be learned from practice of the
disclosure. The objectives and other advantages of the disclosure
may be realized and attained by the structure particularly pointed
out in the written description and claims hereof as well as the
appended drawings.
To achieve these and other advantages and in accordance with the
purpose of the disclosure, as embodied and broadly described
herein, the present disclosure provides a rollable display in which
a back plate, which serves to support a display panel, is variable
in shape so as to be stored in a folded state inside an
accommodating case using different characteristics thereof for each
area without separate mechanical equipment.
According to one aspect of the present disclosure, a rollable
display including a flexible display panel including a first
surface as a display surface and a second surface as a rear
surface, a back plate disposed in contact with the second surface
and including an inner folding portion and an outer folding portion
alternately arranged with an unfolding portion therebetween, and an
accommodating case including therein an opening, through which the
flexible display panel and the back plate are integrally introduced
or discharged, and configured to accommodate therein the flexible
display panel and the back plate, which are integrally folded at
the inner folding portion and the outer folding portion.
The accommodating case may include a space having a height equal to
or greater than a sum of a curvature of the inner folding portion,
a curvature of the outer folding portion, and a length of the
unfolding portion between the inner folding portion and the outer
folding portion.
When folded inside the accommodating case, the back plate may be
located at an inner side and the first surface of the flexible
display panel may be located at an outer side in the inner folding
portion, and the back plate may be located at an outer side and the
first surface of the flexible display panel may be located at an
inner side in the outer folding portion.
Each of the inner folding portion and the outer folding portion of
the back plate may have a specific gravity lower than that of the
unfolding portion.
Each of the inner folding portion and the outer folding portion of
the back plate may include therein a plurality of openings or a
plurality of holes. Here, each hole may be larger than 1/2 of a
thickness of the back plate.
The outer folding portion of the back plate may have a width
greater than a width of the inner folding portion.
The back plate may further include a step-compensation layer on at
least one of an upper surface or a lower surface thereof. The
openings or holes may be filled with the step-compensation
layer.
The rollable display may further include a capping member provided
on one side of the flexible display panel and the back plate, which
are integrally introduced or discharged through the opening.
The rollable display may further include a pad member provided on a
side of the flexible display panel opposite the one side provided
with the capping member.
The rollable display may further include a printed circuit board
provided in the accommodating case so as to be electrically
connected to a flexible film, which is connected to the pad
member.
The pad member may be connected to a flexible printed circuit
board.
The flexible printed circuit board may be attached and fixed inside
the accommodating case.
The rollable display may further include a support member disposed
adjacent to the opening in the accommodating case and serving to
support the first surface of the display panel and a surface of the
back plate that is not in contact with the second surface.
The back plate may include a plurality of inner folding portions
and a plurality of outer folding portions, adjacent inner folding
portions, which are spaced apart from each other by one outer
folding portion and by unfolding portions at opposite sides thereof
outside the accommodating case, may be brought into contact with
each other when the back plate is folded in the accommodating case,
and adjacent outer folding portions, which are spaced apart from
each other by one inner folding portion and by unfolding portions
at opposite sides thereof outside the accommodating case, may be
brought into contact with each other when the back plate is folded
in the accommodating case.
In addition, the rollable display may include a display unit and a
link unit, so that the display unit may be folded and unfolded so
as to alternately implement inward folding and outward folding
multiple times during folding of the link unit.
It is to be understood that both the foregoing general description
and the following detailed description of the present disclosure
are exemplary and explanatory and are intended to provide further
explanation of the disclosure as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further
understanding of the disclosure and are incorporated in and
constitute a part of this application, illustrate aspect(s) of the
disclosure and together with the description serve to explain the
principle of the disclosure.
FIG. 1 is a view illustrating a general rollable display;
FIG. 2 is a cross-sectional view illustrating the wound state of a
rollable display according to a first aspect of the present
disclosure;
FIG. 3 is a cross-sectional view illustrating the unfolded state of
the rollable display of FIG. 2;
FIG. 4 is a perspective view illustrating the rollable display of
FIG. 2 inside an accommodating case;
FIG. 5 is a plan view illustrating a flexible display panel of FIG.
2 alone;
FIG. 6 is a cross-sectional view illustrating the flexible display
panel according to the present disclosure;
FIGS. 7A and 7B are plan views illustrating areas B and A of FIG.
2;
FIG. 8 is a plan view illustrating a back plate of FIG. 2;
FIGS. 9A to 9F are cross-sectional views of area A or area B of the
back plate illustrated in FIG. 2 according to various aspects;
FIG. 10 is a perspective view illustrating a rollable display
according to a second aspect of the present disclosure;
FIGS. 11 to 13 are reference views illustrating the state in which
the rollable display of FIG. 10 is gradually unfolded;
FIG. 14A is a side view illustrating the side surface of FIG.
12;
FIG. 14B is a side view illustrating the side surface of FIG. 13;
and
FIG. 15 is a reference view illustrating a portion of the interior
of FIG. 10.
DETAILED DESCRIPTION
Hereinafter, exemplary aspects according to the present disclosure
will be described in detail with reference to the accompanying
drawings. Wherever possible, the same reference numbers will be
used throughout the drawings to refer to the same or like parts. In
addition, in the following description of the aspects, a detailed
description of known functions and configurations incorporated
herein will be omitted when it may impede the understanding of the
aspects. In addition, the names of constituent elements used in the
following description are selected in consideration of ease of
writing of the specification, and may differ from names of parts of
actual products.
Further, it will be understood that, when an element or a layer is
referred to as being "on" another element, it can be directly on
the other element or layer or intervening elements or layers may
also be present. On the other hand, it will be understood that,
when an element or a layer is referred to as being "in contact
with" another element, it is directly on the other element without
intervening elements or layers therebetween.
In the drawings, the thickness or size of each constituent element
is illustrated for clarity and convenience, and the present
disclosure is not necessarily limited to the illustrated thickness
or size of the constituent element.
Hereinafter, exemplary aspects of the present disclosure will be
described with reference to the drawings.
FIG. 2 is a cross-sectional view illustrating the wound state of a
rollable display according to a first aspect of the present
disclosure, and FIG. 3 is a cross-sectional view illustrating the
unfolded state of the rollable display of FIG. 2. In addition, FIG.
4 is a perspective view illustrating the rollable display of FIG. 2
inside an accommodating case.
As illustrated in FIGS. 2 to 4, the rollable display according to
the first aspect of the present disclosure, which is designated by
reference numeral 1000, includes a flexible display panel 100,
which includes a first surface as a display surface and a second
surface as a rear surface, a back plate 200, which is in contact
with the second surface of the flexible display panel 100 and
includes an inner folding portion B and an outer folding portion A
alternately arranged with an unfolding portion therebetween, and an
accommodating case 400, which has therein an introduction/discharge
opening 405, through which the display panel 100 and the back plate
200 are integrally introduced or discharged, and which accommodates
therein the display panel 100 and the back plate 200, which are
integrally folded at the inner folding portion B and the outer
folding portion A.
The flexible display panel 100 serves to display an image. For
example, the flexible display panel 100 may use a self-illuminating
flexible display panel 100, like an organic light-emitting display
panel. In the rollable display of the present disclosure, as
illustrated in FIGS. 2 and 3, the flexible display panel 100 is
repeatedly wound and unwound together with the back plate 200, and
displays an image in the unwound state thereof. The back plate 200
may implement folding when accommodated inside the accommodating
case 400 owing to different shapes thereof for each area, without a
separate member. The flexible display panel 100 may be sufficiently
thin, and may have a modulus lower than that of a major material of
the back plate 200 so as to implement folding together with the
back plate 200.
Considering the external appearance of the rollable display, the
accommodating case 400, the first surface of the flexible display
panel 100, which protrudes from the accommodating case 400 to
display an image thereon, the rear surface of the back plate 200
(which is a surface opposite the flexible display panel 100)
attached to the second surface of the flexible display panel 100,
and a capping member 600, which is provided on one side of the
display panel 100 and the back plate 200 to perform an
encapsulation function, are visible. The capping member 600 is
formed of silicon, epoxy, acrylic resin, or the like.
The flexible display panel 100 and the back plate 200 have a
substantially rectangular shape when unfolded, without being
limited thereto. Alternatively, the flexible display panel 100 and
the back plate 200 may be modified to have four rounded corners, or
may be modified to have a polygonal or circular shape, other than
the rectangular shape.
The back plate 200 is formed of a stainless steel plate, and one
surface thereof faces the lower surface of the flexible display
panel 100. That is, the facing surfaces of the flexible display
panel 100 and the back plate 200 are aligned with each other, so
that the flexible display panel 100 and the back plate 200 are
integrally folded inside the accommodating case 400, and are
integrally unfolded outside the accommodating case 400. An adhesive
layer (not illustrated) may be provided between the flexible
display panel 100 and the back plate 200. Since the flexible
display panel 100 and the back plate 200 integrally implement
winding and unwinding inside and outside the accommodating case
400, the adhesive layer may be evenly provided on the second
surface of the flexible display panel 100.
Referring to FIG. 2, the accommodating case 400 may have a space
having a height IH equal to or greater than the sum of the
curvature (1.5R) of the inner folding portion B, the curvature
(1.5R) of the outer folding portion A, and the length of the
unfolding portion UF between the inner folding portion B and the
outer folding portion A. That is, when the accommodating case 400
has a height "3R+h", which is the smallest inner thickness, the
inner folding portion B and the outer folding portion A may come
into contact with the inner surface of the accommodating case 400.
In addition, in order to reduce the longitudinal length (in the X
direction) of the accommodating case 400, the rollable display of
the present disclosure is configured, for example, in a manner such
that adjacent areas of the back plate 200 at the outer folding
portion A are in contact with each other and adjacent areas of the
flexible display panel 100 at the inner folding portion B are in
contact with each other.
The curvature illustrated in FIG. 2 is an example, and is not
limited thereto. The curvature may be set to be larger or smaller
than this, and may be controlled depending on the height of the
accommodating case 400.
The back plate 200 may include a plurality of inner folding
portions B and a plurality of outer folding portions A. Adjacent
inner folding portions B, which are spaced apart from each other by
one outer folding portion A and unfolding portions UF at opposite
sides thereof outside the accommodating case 400, may be brought
into contact with each other when the back plate 200 is folded in
the accommodating case 400. Adjacent outer folding portions A,
which are spaced apart from each other by one inner folding portion
B and unfolding portions UF at opposite sides thereof outside the
accommodating case 400, may be brought into contact with each other
when the back plate 200 is folded inside the accommodating case
400.
When folded inside the accommodating case 400, the back plate 200
is located at the inner side and the first surface of the flexible
display panel 100 is located at the outer side in the inner folding
portion B, whereas the back plate 200 is located at the outer side
and the first surface of the flexible display panel 100 is located
at the inner side in the outer folding portion A.
Each of the inner folding portion B and the outer folding portion A
of the back plate 200 may have a specific gravity lower than that
of the unfolding portion UF.
To this end, the back plate 200 is variable to any of various
shapes, and the rollable display of the present disclosure has a
feature in that the inner folding portion B or the outer folding
portion A has an opening or a hole that is formed in a part of the
thickness thereof, unlike the unfolding portion UF. A description
thereof will be made below.
The flexible display panel 100 may include a pad member (not
illustrated) on the side thereof opposite the side thereof provided
with the capping member 600 (shown as "PAD" in FIG. 5).
Alternatively, the pad member PAD of the flexible display panel 100
may be connected to a flexible film such as a COF, and a printed
circuit board 500 may further be provided inside the accommodating
case 400 so as to be electrically connected to the flexible film.
Here, the printed circuit board 500 may be attached and fixed to
the inner side portion or the inner lower surface of the
accommodating case 400. In this case, the printed circuit board 500
takes the form of a hard board, and an electrical signal is
transmitted from the printed circuit board 500 to the pad member
PAD through a wire provided in the flexible film.
Alternatively, as illustrated in FIG. 2, the pad member PAD of the
flexible display panel 100 and the flexible printed circuit board
500 may be directly connected to each other. Here, the other side
portion of the flexible display panel 100, on which the flexible
printed circuit board 500 is located, may be fixed in the
accommodating case 400 using a fixing member 330.
As illustrated, support members 310 and 320 may further be provided
adjacent to the introduction/discharge opening 405 in the
accommodating case 400 to support the first surface of the flexible
display panel 100 and the surface of the back plate 200 opposite
the second surface of the flexible display panel 100. The support
members 310 and 320 may push the flexible display panel 100 and the
back plate 200 so as to allow the two to smoothly move out through
the introduction/discharge opening 405.
FIG. 5 is a plan view illustrating the flexible display panel of
FIG. 2 alone, and FIG. 6 is a cross-sectional view illustrating the
flexible display panel according to the present disclosure.
In FIG. 5, it is conceivable that the flexible display panel 100
moves out through the introduction/discharge opening in the
vertical direction. Here, the capping member 600 is provided on one
side of the flexible display panel 100, and the pad member PAD is
provided on the other side of the flexible display panel 100. The
pad member PAD of the flexible display panel 100 may be directly
connected to the printed circuit board 500, or may be connected to
the printed circuit board 500 with the flexible film, such as a
COF, interposed therebetween, as described above. As illustrated in
FIG. 2, the printed circuit board 500 is fixed to the back plate
200 and to the flexible display panel 100 using the fixing member
330. In some cases, when the printed circuit board 500 is connected
to the pad member PAD with the flexible film interposed
therebetween, the printed circuit board 500 may be formed of a hard
material so as to be fixed to the inner side portion or the inner
lower surface of the accommodating case 400, or may be configured
with a flexible printed circuit board using a flexible
material.
The flexible display panel 100 independently implements display,
and in order to maintain flexibility, a flexible base material
(shown as 112 in FIG. 5) thereof, on which, for example, a
thin-film transistor array is disposed, may be formed of a flexible
plastic film or organic material. The flexible base material 112
has an approximate thickness ranging from 3 .mu.m to 100 .mu.m, and
the overall approximate thickness of the flexible display panel 100
ranges from 5 .mu.m to 300 .mu.m even when it includes the array
formed on the flexible base material 112, so that the display panel
100 may be folded by folding or bending any region thereof.
However, in the rollable display as a finished product, a folding
region FR may be set to a specific region depending on the device
requirements. The folding region FR may be specified as having
different configurations for each area depending on the
requirements of any other constituent element, i.e. the back plate
200, excluding the display panel 100. In some cases, in order to
secure sufficient flexibility during a folding operation and to
prevent damage to the array, the flexible display panel 100 may
include the flexible base material 112, which has different array
shapes or different surface structures in the folding region FR and
the unfolding region UFR.
As illustrated in FIG. 6, a buffer layer 120 is formed on a
flexible substrate (the flexible base material 112), and a
thin-film transistor Tr is formed on the buffer layer 120. The
buffer layer 120 may be omitted.
A semiconductor layer 122 is formed on the buffer layer 120. The
semiconductor layer 122 may be formed of an oxide semiconductor
material or polycrystalline silicon.
When the semiconductor layer 122 is formed of an oxide
semiconductor material, a light-blocking pattern (not illustrated)
may be formed below the semiconductor layer 122. The light-blocking
pattern prevents light from being incident on the semiconductor
layer 122, thereby preventing the semiconductor layer 122 from
being deteriorated by light. Unlike this, the semiconductor layer
122 may be formed of polycrystalline silicon, in which case
opposite edges of the semiconductor layer 122 may be doped with a
dopant.
A gate insulation layer 124 is formed on the semiconductor layer
122 using an insulating material. The gate insulation layer 124 may
be formed of an inorganic insulating material such as silicon oxide
or silicon nitride.
A gate electrode 130 is formed on the gate insulation layer 124
using a conductive material such as a metal so as to correspond to
the center of the semiconductor layer 122.
Although the gate insulation layer 124 is illustrated as being
formed over the entire surface of the flexible base material 112 in
FIG. 6, the gate insulation layer 124 may alternatively be
patterned to have the same shape as the gate electrode 130.
An interlayer insulation film 132 is formed on the gate electrode
130 using an insulating material. The interlayer insulation film
132 may be formed of an inorganic insulating material such as
silicon oxide or silicon nitride, or may be formed of an organic
insulating material such as benzocyclobutene or photo-acryl.
The interlayer insulation film 132 has therein first and second
contact holes 134 and 136, which expose opposite sides of the
semiconductor layer 122. The first and second contact holes 134 and
136 are located at opposite sides of the gate electrode 130 so as
to be spaced apart from the gate electrode 130.
Here, the first and second contact holes 134 and 136 are also
formed in the gate insulation layer 124. Unlike this, when the gate
insulation layer 124 is patterned to have the same shape as the
gate electrode 130, the first and second contact holes 134 and 136
may be formed only in the interlayer insulation film 132.
A source electrode 140 and a drain electrode 142 are formed on the
interlayer insulation film 132 using a conductive material such as
a metal.
The source electrode 140 and the drain electrode 142 are located so
as to be equidistantly spaced apart from the gate electrode 130,
and are brought into contact with opposite sides of the
semiconductor layer 122 through the first and second contact holes
134 and 136, respectively.
The semiconductor layer 122, the gate electrode 130, the source
electrode 140, and the drain electrode 142 constitute the thin-film
transistor Tr, and the thin-film transistor Tr functions as a
driving element.
The thin-film transistor Tr may have a coplanar structure in which
the gate electrode 130, the source electrode 142, and the drain
electrode 144 are located on the semiconductor layer 120.
Unlike this, the thin-film transistor Tr may have an inverted
staggered structure in which the gate electrode is located below
the semiconductor layer and the source electrode and the drain
electrode are located above the semiconductor layer. In this case,
the semiconductor layer may be formed of amorphous silicon.
Although not illustrated, a gate line and a data line cross each
other to define a pixel area, and a switching element is further
formed so as to be connected to the gate line and the data line.
The switching element is connected to the thin-film transistor Tr,
which serves as the driving element.
In addition, a power line may be spaced apart from and parallel to
the gate line or the data line, and a storage capacitor may further
be provided in order to allow the gate electrode of the thin-film
transistor Tr, serving as the driving element, to maintain a
constant voltage during one frame.
A protective layer 145, which has therein a drain contact hole 152
for exposing the drain electrode 142 of the thin-film transistor
Tr, is formed so as to cover the thin-film transistor Tr. Thin-film
transistors Tr having the same shape described above are provided
in respective pixel areas, and the thin-film transistors Tr
provided on the flexible base material 112 are collectively
referred to as a thin-film transistor array.
A first electrode 160 is discretely formed on the protective layer
145 for each pixel area so as to be connected to the drain
electrode 142 of the thin-film transistor Tr through the drain
contact hole 152. The first electrode 160 may be an anode, and may
be formed of a conductive material having a relatively large work
function value. For example, the first electrode 160 may be formed
of a transparent conductive material, such as indium-tin-oxide
(ITO) and indium-zinc-oxide (IZO), or may be configured with a
multilayered electrode including at least one layer of transparent
conductive material.
In the case in which the display panel 100 of the present
disclosure is of a top-emission type, a reflective electrode or a
reflective layer may further be formed below the first electrode
160. For example, the reflective electrode or the reflective layer
may be formed of an aluminum-palladium-copper (APC) alloy. In some
cases, a transparent conductive material may further be provided
below the reflective electrode.
In addition, a bank layer 166 is formed on the protective layer 145
so as to cover the edge of the first electrode 160. The bank layer
166 corresponds to the pixel area and exposes the center of the
first electrode 160.
An organic emission layer 162 is formed on the first electrode 160.
The organic emission layer 162 may take the form of a single layer
formed of a light-emitting material. In addition, in order to
increase luminous efficacy, the organic emission layer 162 may have
a multilayered structure including a hole injection layer, a hole
transport layer, a light-emitting material layer, an electron
transport layer, and an electron injection layer, which are
sequentially stacked on the first electrode 160.
A second electrode 164 is formed on the organic emission layer 162
above the flexible base material 112. The second electrode 164 may
be located over the entirety of a display area, and may be a
cathode formed of a conductive material having a relatively small
work function value. For example, the second electrode 164 may be
formed of any one of aluminum (Al), magnesium (Mg), silver (Ag),
ytterbium (Yb), an aluminum alloy, for example AlMg, and silver
alloy, for example, AgMg.
The first electrode 160, the organic emission layer 162, and the
second electrode 164 constitute an organic light-emitting diode D.
The organic light-emitting diode D is provided in each pixel area
so as to be connected to the thin-film transistor Tr, and organic
light-emitting diodes formed in all of the pixel areas are also
collectively referred to as an organic light-emitting diode.
An encapsulation film 170 is formed on the second electrode 164 in
order to prevent external moisture from entering the organic
light-emitting diode D. The encapsulation film 170 may take the
form of a stack including a first inorganic insulation layer 172,
an organic insulation layer 174, and a second inorganic insulation
layer 176, but is not limited thereto as long as it is formed by
alternately stacking an inorganic insulation layer and an organic
insulation layer so that the outermost layer is an inorganic
insulation layer.
In addition, a touch electrode array including a first touch
electrode 181 and a second touch electrode 182 may further be
provided on the encapsulation film 170 in order to detect a touch.
In the illustrated form, a bridge line 181a is provided on the
second inorganic insulation layer 176, which is the outermost
layer, a touch insulation layer 183 is provided on the bridge line
181a, and a first touch pattern 181b and the second touch electrode
182 are spaced apart from each other on the touch insulation layer
183. Here, the first touch pattern 181b is electrically connected
to the bridge line 181a through a contact hole in the touch
insulation layer 183 so as to configure the first touch electrode
181. In the drawing, only a portion of the second touch electrode
182 is illustrated. The second touch electrode 182 is located on a
portion of the touch insulation layer 183 in which the first touch
pattern 181b is not located, and generates mutual capacitance Cm
between first and second touch patterns 181b that are spaced apart
from each other.
The presence or absence of a touch may be detected based on
variation in mutual capacitance Cm.
The illustrated touch electrode array is given by way of example,
and the disclosure is not limited thereto. Although the touch
electrode array may be directly formed on the encapsulation film
170, as illustrated, a separate material or insulation layer may
further be provided so that the touch electrode array is disposed
thereon, or the touch electrode array may be provided inside a
cover film. In some cases, the encapsulation film 170 may be
located on the top of the display panel 100 without providing the
touch electrode array.
A polarizer (not illustrated) may be attached on the touch
electrode array in order to reduce the reflection of external
light. For example, the polarizer may be a circular polarizer.
Alternatively, a cover layer such as a cover window may further be
provided in order to protect the top of the touch electrode
array.
Reference numeral "1100", not described above, denotes an array
structure including all of an array of the thin-film transistors Tr
formed on the flexible base material 112, an array of the organic
light-emitting diodes D connected to the respective thin-film
transistors Tr, the encapsulation layer 170 covering the
aforementioned constituents, and a touch electrode array 181, 182
and 183.
The display panel described above is given by way of example, and
is an organic light-emitting display panel, but may be replaced
with any other type of display panel as long as it is flexible. For
example, the organic light-emitting display panel described above
may be replaced with a flexible liquid-crystal panel, a flexible
quantum-dot display panel, or a flexible electrophoretic display
panel.
In the rollable display of the present disclosure, as described
above with reference to FIGS. 2 to 4, the flexible display panel
100 and the back plate 200 are integrally rolled inside the
accommodating case 400 in the state in which they are bonded to
face each other. Considering the shape of the rollable display, an
inward folding structure in which the back plate 200 is rolled
inwards, a predetermined unfolding structure, an outward folding
structure in which the back plate 200 is rolled outwards, and the
unfolding structure are repeatedly deployed. In this case, the
flexible display panel 100 implements inward folding and outward
folding in the inverted shape of inward folding and outward folding
of the back plate 200. In this case, such inward folding and
outward folding are obtained by different shapes of the back plate
200 for each area, without a separate member. That is, as
illustrated in FIG. 3, when a display unit of the flexible display
panel 100 and the back plate 200, which are integrally unfolded, is
introduced into the limited space in the accommodating case 400, as
illustrated in FIG. 2, a specific area of the back plate 200 is
rolled inwards or outwards due to different patterns of the back
plate 200 for each area, and the remaining area remains unfolded.
In this case, inward folding and outward folding are repeated to
compensate for each other, so that no slippage occurs between the
flexible display panel 100 and the back plate 200.
FIGS. 7A and 7B are plan views illustrating areas B and A of FIG.
2.
FIG. 7A illustrates the inner folding portion B. An unfolding
portion 210 remains in a plate state, but a plurality of openings
or holes 207 for inward folding are formed in the inner folding
portion B.
Referring to FIG. 7A, a single opening or hole is formed in a first
pattern in an odd-numbered column, and two openings or holes are
formed in a second pattern in an even-numbered column. However, the
first pattern may include two or more openings or holes, and the
second pattern may include three or more openings or holes.
Each of the first and second patterns is configured so as to extend
in the column direction. That is, the major axis of each of the
first and second patterns may be parallel to the column
direction.
Accordingly, the inner folding portion, in which the openings 207
are formed, serves as a spring to increase the elastic restoration
energy of the back plate 200 during repeated folding and unfolding
operations. Thus, when the rollable display is again changed to an
unfolded state so that folding stress is removed, the time taken
until the rollable display returns to the original state thereof
may be reduced.
The openings 207 in the patterns may be modified to a polygonal or
elliptical shape that is elongated in the folding axis direction,
or may be modified to a polygonal shape having respective rounded
corners.
The opening patterns including the openings 207, as illustrated in
FIG. 7A, may include pairs of first and second patterns having the
same shape, and may be repeated in the entire inner folding portion
IF. Alternatively, the opening patterns having the same shape may
be gradually densely or loosely arranged from the center to the
edge of the inner folding portion IF. In some cases, random opening
patterns may be provided merely to differentiate the inner folding
portion IF from the unfolding portion 210. The first and second
patterns may be disposed so that the longitudinal direction thereof
coincides with the folding axis direction. That is, the openings
207 may be elongated in the folding axis direction.
The back plate 200 is located below the flexible display panel 100
and supports the display panel 100. The back plate 200 has
stiffness greater than the flexible base material 112. That is, the
back plate 200 may have a Young's modulus greater than that of the
flexible base material 112.
For example, the back plate 200 may be formed of a high-stiffness
material such as stainless steel, and therefore, may have higher
restoring force and greater stiffness than other materials, which
may cause a reduction in the thickness of the back plate 200.
That is, when the back plate 200 is formed of a high-stiffness
material such as stainless steel, the back plate 200 may maintain
desired stiffness even if the thickness thereof is reduced, thereby
serving to support the flexible display panel 100. In addition,
such a reduction in thickness may reduce plastic deformation of the
back plate 200.
However, the back plate 200, which is formed of a high-stiffness
material and has a small thickness, is very difficult to restore
once it has been deformed because of the narrow elastic deformation
range thereof. That is, the back plate 200 may not be unfolded
after being folded, and the time during which the folded shape is
maintained is increased.
Although the shape in which a long rectangle and a short rectangle
are alternately repeated is illustrated, the shape of the opening
patterns is not limited thereto, and rectangles having the same
shape may be repeated. In addition, the shape of the openings or
holes 207 is not limited to a rectangular shape, and may be any of
a circular shape, other polygonal shapes, an elliptical shape, or
variations thereof.
FIG. 7B illustrates the outer folding portion A (OF). The unfolding
portion 210 (UF) remains in a plate shape, but a plurality of
openings or holes 205 for outward folding are formed in the outer
folding portion OF. The openings or holes 205 are illustrated as
being formed to have a dumbbell shape in plan, but are not limited
thereto, and may be modified in various ways, as in the
above-described inner folding portion B (IF).
It is to be noted that the inner folding portion B and the outer
folding portion A occupy different lengths of areas of the back
plate 200, so that the area occupied by the openings or holes 205
in the outer folding portion OF is wider than the area occupied by
the openings or holes 207 in the inner folding portion IF.
Here, the openings or holes 207 for inward folding function to
reduce the specific gravity of the area, in which folding occurs,
compared to the unfolding portion 210 having a relatively large
modulus, thereby causing the area to serve as a spring. Although
the back plate 200, used in the rollable display of the present
disclosure, may be formed of a high-stiffness material so as to
support the flexible display panel 100 even with a small thickness
ranging from 2 mm to 3 mm, when the back plate 200 is formed of
only such a high-stiffness material, it may have difficulty in
returning to the original state thereof after external force is
applied thereto. To prevent this, as illustrated in FIGS. 7A and
7B, the openings or holes 207 and 205 are formed in the inner
folding portion and the outer folding portion so as to increase the
restoring force of the back plate 200. That is, it is possible to
provide a back plate 200 having a small thickness and high
restoring force.
FIGS. 7A and 7B illustrate the openings or holes 207 for inward
folding and the openings or holes 205 for outward folding according
to one example, and the openings or holes 207 and 205 may have the
same shape, but may be formed in the areas IF and OF having
different widths due to the difference in area (i.e., path).
FIG. 8 is a plan view illustrating the back plate of FIG. 2, and
FIGS. 9A to 9F are cross-sectional views of area A or area B of the
back plate illustrated in FIG. 2 according to various aspects.
The material of the back plate 200 in the rollable display of the
present disclosure is a ferrous alloy having stiffness, such as
stainless steel, in which an alloy element excluding steel is 50%
or less and the content of chrome (Cr) therein ranges from 7% to
32%. In addition to the steel and chrome, the back plate 200 may
further include a metal such as nickel and a non-metal material
such as silicon (Si).
As illustrated in FIG. 8, since the back plate 200 needs to
repeatedly implement inward folding and outward folding, the inner
folding portion IF, in which the openings or holes for inward
folding are formed, and the outer folding portion OF, in which the
openings or holes for outward folding are formed, are alternately
repeated with the unfolding portion UF (which includes no opening
or hole and is formed of stainless steel) interposed
therebetween.
Considering the cross-sectional configuration in detail, different
first and second patterns, which have the planar shape illustrated
in FIG. 7A described above, are respectively designated by 202a and
202b.
FIGS. 9A to 9F are cross-sectional views illustrating openings or
holes, which may be applied to the inner folding portion IF or the
outer folding portion OF of the back plate 200. The openings or
holes may have the same cross-sectional shape, and thus are
designated by the same reference numeral "202".
The openings 202, which include the first pattern 202a formed in
the (2n-1).sup.st column and the second patterns 202b formed in the
(2n).sup.th column, is formed (here, "n" is a positive
integer).
Each of the first and second patterns 202a and 202b may have a
rectangular shape. In addition, the space between the second
patterns 202b formed in the (2n).sup.th columns may correspond to
the first pattern 202a formed in the (2n-1).sup.st column.
In the back plate 200, as illustrated in FIGS. 9A and 9C to 9F, in
order to prevent an area including the openings 202 from being
stepped and to protect the back plate 200, first and second
step-compensation layers 211 and 213 may be formed on the lower
surface and the upper surface of the back plate 200. Here, the
step-compensation layers 211 and 213 are formed of a material
having stiffness lower than that of a body 200a of the back plate
200. For example, each of the first and second step-compensation
layers 211 and 213 may be formed of one of polyurethane (PU),
thermoplastic polyurethane (TPU), polyacrylate, rubber, and silicon
(Si).
In this case, the first and second step-compensation layers 211 and
213 cover the openings 202 to protect the same and eliminate any
stepped portion. Through the provision of the first and second
step-compensation layers 211 and 213, it is possible to prevent any
display defect that may be caused by the openings 202.
Any one of the first and second step-compensation layers 211 and
213 may be formed, and may be selectively formed only in the
folding region FR.
In some cases, as illustrated in FIG. 9D, one of the first and
second step-compensation layers 211 and 213 may be formed so as to
fill the openings 202. Here, a step-compensation layer 211a, which
fills the openings 202 in the inner folding portion IF or the outer
folding portion OF, may have stiffness lower than that of the back
plate 200 formed of stainless steel, and thus may remain reliable
even during repeated folding operations of the folding region
FR.
Here, FIG. 9B illustrates the most basic configuration of the back
plate 200, which includes the inner folding portion IF and the
outer folding portion OF, but includes no step-compensation layer
so that the openings 202 (202a and 202b) are exposed from the
surface thereof. When the back plate 200 having the cross-sectional
structure illustrated in FIG. 9B is disposed so as to face the
flexible display panel 100, an adhesive layer therebetween may fill
the openings 202 to perform attachment between the back plate 200
and the flexible display panel 100.
The openings 202 may have a length equal to a partial thickness P1
of the body 200, as illustrated in FIG. 9A, or may have a length
equal to the entire thickness P2 of the body 200a, as illustrated
in FIG. 9B or 9C. As illustrated in FIG. 9E, the openings 202,
which have a length equal to a partial thickness P1 or P3, may be
alternately located in the upper surface and the lower surface of
the body 200a. As illustrated in FIG. 9F, the opening 202, which
has a length equal to the partial thickness P1 of the body 200a,
and the opening 202, which has a length equal to the entire
thickness P2 of the body 200a, may be alternately located.
When the openings 202 of FIG. 9E or 9F are formed to have a length
equal to the partial thickness P1, the thickness P1 needs to be
greater than 1/2 of the thickness of the body 200a, which may be
desirable in terms of stretching and contraction of the openings
202.
As described above, the rollable display of the present disclosure
includes the high-stiffness back plate 200 to support the display
panel 100, and the back plate 200 is configured to have different
patterns in the inner folding portion, the outer folding portion,
and the unfolding portion therebetween, which may cause the outer
folding portion and the inner folding portion to compensate for
each other. Thereby, it is possible to prevent slippage between the
back plate and the flexible display panel, and consequently to
improve visibility.
In particular, the rollable display of the present disclosure is
configured to repeatedly implement tension and compression, which
may prevent slippage of the rollable display that is wound in a
given direction, and waviness in display due thereto.
In the rollable display of the present disclosure, the inner
folding portion, the outer folding portion, and the unfolding
portion therebetween configure one set, and a plurality of sets
thereof is provided inside the accommodating case. With this
configuration, the display surface of the rollable display may be
expanded in the fully unfolded state thereof, which results in
higher efficiency of utilization of the display surface for a given
area of the accommodating case.
In addition, the rollable display of the present disclosure enables
automatic inward folding and outward folding of the back plate
inside the accommodating case owing to the formation of
differentiated patterns of the back plate without a specific
mechanical member.
FIG. 10 is a perspective view illustrating a rollable display
according to a second aspect of the present disclosure, FIGS. 11 to
13 are reference views illustrating the state in which the rollable
display of FIG. 10 is gradually unfolded, FIG. 14A is a side view
illustrating the side surface of FIG. 12, and FIG. 14B is a side
view illustrating the side surface of FIG. 13.
Referring to FIGS. 10 to 13, the rollable display according to the
second aspect of the present disclosure, which is designated by
reference numeral 2000, includes a display unit DP and a link unit
700. Here, the rollable display 2000 according to the second aspect
of the present disclosure uses the name "rollable display" since
the display unit DP implements folding multiple times, but may also
be applied to the field of a foldable display.
The display unit DP includes the flexible display panel 100 and the
back plate 200. Here, a detailed description of the display unit DP
is the same as the above description of the flexible display panel
100 and the back plate 200, and thus will be omitted below.
As illustrated in FIG. 8, the back plate 200 is composed of the
folding portions IF and OF and the unfolding portions UF, and the
folding portions include the outer folding portions OF and the
inner folding portions IF, which are alternately arranged, so that
the display unit DP is rolled or folded in a zigzag pattern.
In the display unit DP described above, the unfolding portions UF
are coupled onto the link unit 700 so that the folding portions OF
and IF are folded and unfolded according to the folding and
unfolding of the link unit 700.
FIG. 11 illustrates the state in which the display unit DP is
unfolded to about 30% from the state of FIG. 10, FIG. 12
illustrates the state in which the display unit DP is unfolded to
about 50% from the state of FIG. 10, and FIG. 13 illustrates the
state in which the display unit DP is unfolded to 100% to become a
plane. Accordingly, the greater the degree of unfolding of the link
unit 700, the more the display unit DP is unfolded, and the more
closely the same resembles the shape of a flat panel display. When
the link unit 700 is completely unfolded, the display unit DP is
unfolded 100% to form a plane.
Here, since the display unit DP includes the outer folding portions
OF and the inner folding portions IF, which are alternately
arranged, the display unit DP is not folded multiple times in a
single direction. This may prevent separation between the flexible
display panel 100 and the back plate 200.
The link unit 700 includes a first shaft 710, a first link joint
711, and a second link joint 712.
The first shaft 710 is coupled to the center of the first link
joint 711, and each end of the first shaft 710 is coupled to the
center of the first link joint 711. In addition, the first shaft
710 may be rotatably coupled to the center of the first link joint
711. This serves to allow the display surface, which is the upper
surface of the display unit DP, to be disposed in a plane while the
link unit 700 is being folded or unfolded in the state in which the
display unit DP is coupled to the first shaft 710. In addition,
this also serves to prevent deformation or damage to the display
unit DP by allowing tensile or compressive stress to be evenly
distributed to each of the folding portion and the unfolding
portion while the display unit DP is being folded or unfolded.
The second link joint 712 is disposed at the outer side of the
first link joint 711, and is coupled at the center thereof to the
first shaft 710, which is a rotating shaft, in the same manner as
the first link joint 711. In addition, the first link joint 711 and
the second link joint 712 may have the same length.
As such, a pair of first link joints 711 is disposed parallel to
each other at both ends of the first shaft 710 and a pair of second
link joints 712 is disposed parallel to each other at both ends of
the first shaft 710 so that substantially "X"-shaped link joints
are provided.
Here, a second shaft 720 and a third shaft 730 are provided
respectively at the front and the rear of the first shaft 710 so as
to be parallel to the first shaft 710 in a first direction.
Similarly, two pairs of first and second link joints 721 and 722
are disposed respectively at both ends of the second shaft 720, and
two pairs of first and second link joints 731 and 732 are disposed
respectively at both ends of the third shaft 730. Then, one end of
the first link joint 711 of the first shaft 710 is connected to the
upper end of the second link joint 722 of the second shaft 720, and
the other end of the first link joint 711 of the first shaft 710 is
connected to the lower end of the second link joint 732 of the
third shaft 730. In addition, one end of the second link joint 712
of the first shaft 710 is connected to the upper end of the first
link joint 731 of the third shaft 730, and the other end of the
second link joint 712 of the first shaft 710 is connected to the
lower end of the first link joint 721 of the second shaft 720. In
this way, the respective link joints may be rotated in cooperation
with each other, and the rotation angle thereof or the distance to
which the display unit DP is unfolded may be the same for each link
joint.
Individual first link joints 711, 721 and 731 and second link
joints 721, 722 and 732 are rotatable relative to each other in
different directions about the rotation axis of respective shafts
710, 720 and 730. For example, when the first link joint 711 is
rotated in a given direction and the second link joint 712 is
rotated in the opposite direction about the rotation axis of the
first shaft 710, the link unit 700 and the display unit DP are
unfolded. Conversely, when the first link joint 711 is rotated in
the opposite direction and the second link joint 712 is rotated in
the given direction about the rotation axis of the first shaft 710,
the display unit DP is folded via a plurality of folding
regions.
One end of the display unit DP is coupled to the printed circuit
board 500. Of course, the printed circuit board 500 may be a
flexible printed circuit board, and may include a drive unit (not
illustrated), although not illustrated in the drawings. Here, the
printed circuit board 500 is formed so as to have a length equal to
or less than the length of the unfolding portion UF of the display
unit DP which is not folded or the length of the first link joint
711 or the second link joint 712. Thus, even in the state in which
the display unit DP is completely folded, the printed circuit board
500 is disposed between the unfolding portions UF so that the
printed circuit board 500 or the drive unit is not exposed to the
outside. Of course, when the printed circuit board 500 or the drive
unit has a greater size, the printed circuit board 500 or the drive
unit may be disposed at the lower side of the link unit 700 or at
the lower side of the display unit DP so as not to be exposed to
the outside during the operation of the display 2000.
FIG. 15 is a reference view illustrating a portion of the interior
of FIG. 10.
Referring to FIG. 15, the display unit DP is provided on the rear
surface thereof with a hook member 250. In the display unit DP, at
least one hook member 250 is disposed in each unfolding portion UF
on the rear surface of the back plate 200. The hook member 250 is
coupled to a corresponding shaft and functions to fix the display
unit DP to the link unit 700. The hook member 250 may first be
coupled to the shaft so that an assembly of the hook member 250 and
the shaft is coupled to the rear surface of the back plate 200.
Alternatively, the hook member 250, which is separate from the
shaft, may be coupled to the rear surface of the back plate 200,
and thereafter, may be interference-fitted to the shaft.
Here, in each unfolding portion UF of the back plate 200, the hook
member 250 coupled to the first shaft 710 and a hook member coupled
to the second shaft or the third shaft may be positioned so as not
to interfere with each other during the folding of the display unit
DP.
In addition, three or more hook members 250 may be provided
equidistantly or at positions close to both ends of one shaft on
the back plate 200.
The hook member 250 may be necessary for each shaft 710, 720 or
730, which is coupled to the center of the first link joint 711,
721 or 731, and a side shaft 713 may be provided so as to
interconnect at least one end of both ends of the respective first
link joints, which face each other. More particularly, the side
shaft 713 is positioned on the lower end of the first link joint
711. Since the display unit DP may maintain a planar form in the
completely unfolded state thereof only when the rear surface of the
display unit DP is supported by the respective shafts, the side
shaft 713 is positioned on the lower end of the first link joint.
Of course, the side shaft 713 may also function to increase
stiffness during the folding of the link unit.
As is apparent from the above description, a rollable display of
the present disclosure has the following effects.
A back plate, which serves to support a flexible display panel, is
divided into a plurality of areas in a manner such that an inner
folding portion and an outer folding portion are alternately
repeated with an unfolding portion therebetween, which makes the
lengths of paths, along which the display panel and the back plate
are folded, equal so as to prevent slippage between the two.
Thereby, a rollable display, in which no visibility defect is
observed, may be realized.
In addition, a display unit is coupled onto a link unit so as to be
folded by alternately repeating inward folding and outward folding.
Thereby, it is possible to provide a rollable display, which is
capable of preventing separation between a flexible display panel
and a back plate and ensuring easy folding of the display unit.
Although the aspects of the present disclosure have been described
above in detail with reference to the accompanying drawings, it
will be apparent to those skilled in the art that the present
disclosure described above is not limited to the aspects described
above, and various substitutions, modifications, and alterations
may be devised within the spirit and scope of the present
disclosure. Thus, such modifications should be considered to fall
within the scope of the present disclosure, and the true technical
scope of the present disclosure should be determined by the
technical ideas of the claims to be set forth below.
* * * * *